BACKGROUND: The Attitudes Toward Intellectual Disability Questionnaire (ATTID) has demonstrated good psychometric qualities for measuring the attitudes of different groups of adults in the general population toward intellectual disability (ID). A significant advantage of the ATTID is that it addresses the concept of attitudes using a three-dimensional model (affective, cognitive and behavioural). To our knowledge, there are no normative data published regarding attitudes toward ID on general population-based samples.METHODS: The sample of 1605 men and women was stratified to be representative of the general adult population of Quebec. The ATTID was administered by phone interview through an independent survey firm.RESULTS: Normative data are presented as percentile scores associated with the raw score of the ATTID by gender and age categories. Analysis of the variance yielded significant differences in attitude by gender and age. The directions and the strength of these associations vary according to each of the five factors used to define attitudes.CONCLUSION: These norms will provide an essential tool to compare different groups and assess the effectiveness of various public campaigns to encourage more positive attitudes towards persons with ID. These norms would also allow international comparisons.